1. Field of the Invention
This invention relates to aqueous preparations containing antimicrobial biguanide compounds, alkyl glycoside surfactants enhancing their effect and homogeneously solubilized water-insoluble aromatic oils which are particularly suitable for use as antiseptic mouthwashes.
Aqueous-alcoholic preparations of aromatic oils preferably containing antimicrobial compounds and surfactants are normally used as mouthwashes. The products are marketed either as clear or opaque, ready-to-use solutions which are used in undiluted form or preferably in the form of concentrates which have to be diluted to the in-use concentration with water before use.
It is an important objective to provide an adequate level of protection against the gram-positive bacteria with minimal concentrations of antibacterial compounds. Because gram-positive bacteria play a role in the formation of tartar and hence in the development of caries, their control is very important.
2. Statement of Related Art
It is known from EP-A-185 971 that this objective can be achieved by a combination of antibacterial biguanide compounds with alkyl glycoside surfactants. It is also known from U.S. Pat. No. 4,198,392 that certain biguanides can be used as oral compositions.
However, mouthwashes should contain organoleptically acceptable aromatic oils which, on the one hand, contribute towards the antimicrobial effect and, on the other hand, provide an agreeable and refreshing taste and impart a deodorizing effect while in use. Water-insoluble aromatic oils suitable for this purpose must be homogeneously solubilized in the mouthwash concentrate so that the concentrate and the in-use solution prepared therefrom remain stable and do not undergo premature separation. Lower pharmaceutically acceptable alcohols, particularly ethanol, and surfactants are normally used for this purpose. However, it is desirable to minimize the ethanol content both for reasons of cost and because of the irritation which relatively high concentrations of ethanol cause to the mucous membrane. This necessitates an increased content of particularly effective aromatic oil solubilizers. However, it has been found that many known solubilizers for aromatic oil reduce the potentiated antimicrobial effect of the system of antimicrobial biguanide compounds and alkyl glycoside surfactants. It is generally necessary as a result of this to increase the concentration of antimicrobial compounds or stronger bacteriacidal substances, for example hydrogen peroxide, or use of relatively high concentrations of ethanol to obtain an adequate antibacterial effect. However, such measures are extremely undesirable for compositions which are applied to the mucous membrane, particularly if they are applied over a relatively long period.
Accordingly, the object of the present invention is to provide flavored compositions containing a low concentration of antimicrobial biguanide compounds and homogeneously solubilized aromatic oils and, in the in-use concentration, no more than 15% by weight ethanol. It has been found that this object can be achieved particularly effectively using special solubilizers and by a specific choice of components both in type and in quantity.